Promethium

Symbol: Pm
Date of discovery: 1945
Name origin: Greek prometheus
Appearance: unknown
Discoverer: J.A. Marinsky, et al.
Obtained from: fission of U, Th or Pu

Melting point: 1371 K
Boiling point: 3273 K
Density[kg/m³]: 7264
Molar volume: 20.23 × 10^-6 m³/mol
Protons/Electrons: 61
Neutrons: 84
Shell structure: 2,8,18,23,8,2
Electron configuration: [Xe]6s24f5
Oxidation state: 3
Crystal structure: hexagonal

Promethium has been found in the spectrum of the star HR465 in Andromeda, but does not occur naturally on earth. Little is known of metallic promethium’s properties; however, promethium salts glow in the dark with a pale blue or green color because they are highly radioactive. Because of its radioactivity, handling promethium requires great care, as it can emit X-rays during its beta decay. Promethium is used in a nuclear battery where photocells convert light into electric current, with a useful battery life of around five years. It is also a beta radiation source for thickness gauges. The element’s name originates from Prometheus of Greek mythology who stole fire from the gods and gave it to mankind.